Machine dishwashing and laundry compositions

ABSTRACT

Detergent compositions comprising an amino tricarboxylic acid with a rapid rate of dissolution in a washing liquor exhibit a reduced tendency to leave calcium carbonate, lime soap and other deposits on substrates being cleaned. Dishwashing and laundry compositions comprising percarbonate bleach and methyl glycine diacetic acid are provided.

TECHNICAL FIELD

The present invention relates to a detergent composition adapted for use in a cleaning method exhibiting improved soil removal.

BACKGROUND OF THE INVENTION

Compositions designed for use in cleaning, particularly in automatic dishwashing and laundry methods are well known and a consistent effort has been made by detergent manufacturers to improve the cleaning and/or rinsing efficiency of said compositions as reflected by many patent publications.

The general problem of the formation of deposits as spots and films on the articles in the wash/rinse, and on the dishwashing and laundry washing machine parts is well known in the art.

Whilst the general problem of deposit formation is known, a full understanding of the many facets of the problem is however still an active area of research.

A range of deposit types can be encountered. The redeposition of soils or the breakdown products thereof, which have previously been removed from the soiled articles in the washload, provides one deposit type. Insoluble salts such as calcium phosphate or carbonate, calcium fatty acid salts (lime soaps), or certain silicate salts are other common deposit types. Composite deposit types are also common. Indeed, once an initial minor deposit forms it can act as a "seeding centre" for the formation of a larger, possibly composite, deposit structure.

Deposit formation can occur on a range of commonly encountered substrate surfaces including a range of fabric types, plastic, glass, metal and china surfaces. Certain deposit types however, show a greater propensity to deposit on certain substrates. For example, lime soap deposit formation tends to be a particular problem on plastic substrates.

The formation of insoluble carbonate and phosphate, especially calcium carbonate and phosphate, deposits are a particular problem in the machine dishwashing art.

The naturally sourced, inlet water to the dishwasher machine can be a sufficient source of Ca²⁺ and Mg²⁺ ions and CO₃ ²⁻ /HCO₃ ⁻ or PO₄ ³⁻ ions to make deposit formation a problem. Whilst the salt softening system, through which the inlet water will pass prior to entry into the main cavity of the dishwasher machine, can be efficient at removing the naturally present Ca²⁺ and Mg²⁺ ions it is inefficient at removing the CO₃ ²⁻ /HCO₃ ⁻ or PO₄ ³⁻ ions which therefore enter into the wash/rinse solution.

The Applicants have now established that both the levels of Ca²⁺ /Mg²⁺ hardness ions and the levels of CO₃ ²⁻ /HCO₃ ⁻ or PO₄ ³ ions in the wash/rinse water of the dishwasher machine are factors controlling calcium carbonate and phosphate deposit formation. Critical levels of all components must be exceeded for deposit formation to occur. These critical levels are to an extent interdependent. Thus, even in wash/rinse solutions containing high levels of one component, deposit formation will not occur in the absence of the critical level of the other component.

The Applicants have now found that deposit formation is a more noticeable problem when using tablet detergent compositions. It is believed that at least some deposit formation occurs before the builder component of the detergent composition has fully dissolved into the wash solution.

It has been surprisingly found that the problem of deposit formation may be effectively ameliorated by the inclusion of amino tricarboxylic acid (ATCA) into the wash solution during the early stages of the wash.

The Applicants have also surprisingly found that the problem of deposit formation may be further ameliorated if the ATCA is delivered to the wash solution prior to the delivery of the detergent builder component.

The Applicants further found that the more effective control of calcium carbonate and phosphate deposition can also lead to benefits in the prevention of the formation of other deposit types, particularly lime soap deposits and silicate deposits.

Lime soap deposits are most commonly encountered when the washload contains fatty soils, which naturally contain levels of free fatty acids, and when lipolytic enzymes are components of the composition. Lipolytic enzymes catalyse the degradation of fatty soils into free fatty acids and glycerol. Silicate is a common component of machine dishwashing compositions, where it is added for its china care capability.

SUMMARY OF THE INVENTION

A detergent composition comprising:

(a) a detergent component selected from the group consisting of a builder and a surfactant; and

(b) an amino tricarboxylic acid or salt thereof wherein said amino tricarboxylic acid has the general formula: ##STR1## where R₁, R₂ and R₃ are alkyl groups or substituted alkyl groups of chain length C1 to C4; n is 0 or 1; and

X is an organic substituent group.

wherein said amino tricarboxylic acid has a rate of dissolution such that in the T50 test method, described herein, the time taken to achieve 50% dissolution of amino tricarboxylic acid is less than 100 seconds.

DETAILED DESCRIPTION OF THE INVENTION

Surfactant

A highly preferred component of the compositions used in this invention is a surfactant system comprising surfactant selected from anionic, cationic, nonionic ampholytic and zwitterionic surfactants and mixtures thereof. Automatic dishwashing machine products should be low foaming in character and thus the foaming of the surfactant system must be suppressed or more preferably be low foaming, typically nonionic in character. The surfactant system is typically present at a level of from 0.2% to 30% by weight, more preferably from 0.5% to 10% by weight, most preferably from 1% to 5% by weight of the compositions.

Laughlin and Heuring on Dec. 30, 1975. A list of suitable cationic surfactants is given in U.S. Pat. No. 4,259,217 issued to Murphy on Mar. 31, 1981. A listing of surfactants typically included in automatic dishwashing detergent compositions is given for example, in EP-A-0414 549 and PCT applications Nos. WO 93/08876 and WO 93/08874.

Nonionic surfactant

Essentially any nonionic surfactants useful for detersive purposes can be included in the compositions. Preferred, non-limiting classes of useful nonionic surfactants are listed below.

Nonionic ethoxylated alcohol surfactant

The alkyl ethoxylate condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide are suitable for use herein. The alkyl chain of the aliphatic alcohol can either be straight or branched, primary or secondary, and generally contains from 6 to 22 carbon atoms. Particularly preferred are the condensation products of alcohols having an alkyl group containing from 8 to 20 carbon atoms with from about 2 to about 10 moles of ethylene oxide per mole of alcohol.

Nonionic ethoxylated/propoxylated fatty alcohol surfactant

The ethoxylated C₆ -C₁₈ fatty alcohols and C₆ -C₁₈ mixed ethoxylated/propoxylated fatty alcohols are suitable surfactants for use herein, particularly where water soluble. Preferably the ethoxylated fatty alcohols are the C₁₀ -C₁₈ ethoxylated fatty alcohols with a degree of ethoxylation of from 3 to 50, most preferably these are the C₁₂ -C₁₈ ethoxylated fatty alcohols with a degree of ethoxylation from 3 to 40. Preferably the mixed ethoxylated/propoxylated fatty alcohols have an alkyl chain length of from 10 to 18 carbon atoms, a degree of ethoxylation of from 3 to 30 and a degree of propoxylation of from 1 to 10.

Nonionic EO/PO condensates with propylene glycol

The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol are suitable for use herein. The hydrophobic portion of these compounds preferably has a molecular weight of from about 1500 to about 1800 and exhibits water insolubility. Examples of compounds of this type include certain of the commercially-available Pluronic™ surfactants, marketed by BASF.

Nonionic EO condensation products with propylene oxide/ethylene diamine adducts

The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylenediamine are suitable for use herein. The hydrophobic moiety of these products consists of the reaction product of ethylenediamine and excess propylene oxide, and generally has a molecular weight of from about 2500 to about 3000. Examples of this type of nonionic surfactant include certain of the commercially available Tetronic™ compounds, marketed by BASF.

Anionic surfactant

Essentially any anionic surfactants useful for detersive purposes are suitable. These can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of the anionic sulfate, sulfonate, carboxylate and sarcosinate surfactants. Anionic sulfate surfactants are preferred.

Other anionic surfactants include the isethionates such as the acyl isethionates, N-acyl taurates, fatty acid amides of methyl tauride, alkyl succinates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated C₁₂ -C₁₈ monoesters) diesters of sulfosuccinate (especially saturated and unsaturated C₆ -C₁₄ diesters), N-acyl sarcosinates. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tallow oil.

Anionic sulfate surfactant

Anionic sulfate surfactants suitable for use herein include the linear and branched primary and secondary alkyl sulfates, alkyl ethoxysulfates, fatty oleoyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, the C₅ -C₁₇ acyl-N-(C₁ -C₄ alkyl) and --N--(C₁ -C₂ hydroxyalkyl) glucamine sulfates, and sulfates of alkylpolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described herein).

Alkyl sulfate surfactants are preferably selected from the linear and branched primary C₁₀ -C₁₈ alkyl sulfates, more preferably the C₁₁ -C₁₅ branched chain alkyl sulfates and the C₁₂ -C₁₄ linear chain alkyl sulfates.

Alkyl ethoxysulfate surfactants are preferably selected from the group consisting of the C₁₀ -C₁₈ alkyl sulfates which have been ethoxylated with from 0.5 to 20 moles of ethylene oxide per molecule. More preferably, the alkyl ethoxysulfate surfactant is a C₁₁ -C₁₈, most preferably C₁₁ -C₁₅ alkyl sulfate which has been ethoxylated with from 0.5 to 7, preferably from 1 to 5, moles of ethylene oxide per molecule.

A particularly preferred aspect of the invention employs mixtures of the preferred alkyl sulfate and alkyl ethoxysulfate surfactants. Such mixtures have been disclosed in PCT patent application No. WO 93/18124.

Anionic sulfonate surfactant

Anionic sulfonate surfactants suitable for use herein include the salts of C₅ -C₂₀ linear alkylbenzene sulfonates, alkyl ester sulfonates, C₆ -C₂₂ primary or secondary alkane sulfonates, C₆ -C₂₄ olefin sulfonates, sulfonated polycarboxylic acids, alkyl glycerol sulfonates, fatty acyl glycerol sulfonates, fatty oleyl glycerol sulfonates, and any mixtures thereof.

Anionic carboxylate surfactant

Suitable anionic carboxylate surfactants include the alkyl ethoxy carboxylates, the alkyl polyethoxy polycarboxylate surfactants and the soaps (`alkyl carboxyls`), especially certain secondary soaps as described herein.

Suitable alkyl ethoxy carboxylates include those with the formula RO(CH₂ CH₂ 0)_(x) CH₂ C00⁻ M⁺ wherein R is a C₆ to C₁₈ alkyl group, x ranges from O to 10, and the ethoxylate distribution is such that, on a weight basis, the amount of material where x is 0 is less than 20% and M is a cation. Suitable alkyl polyethoxy polycarboxylate surfactants include those having the formula RO--(CHR₁ --CHR₂ --O)--R₃ wherein R is a C₆ to C₁₈ alkyl group, x is from 1 to 25, R₁ and R₂ are selected from the group consisting of hydrogen, methyl acid radical, succinic acid radical, hydroxysuccinic acid radical, and mixtures thereof, and R₃ is selected from the group consisting of hydrogen, substituted or unsubstituted hydrocarbon having between 1 and 8 carbon atoms, and mixtures thereof.

Suitable soap surfactants include the secondary soap surfactants which contain a carboxyl unit connected to a secondary carbon. Preferred secondary soap surfactants for use herein are water-soluble members selected from the group consisting of the water-soluble salts of 2-methyl-1-undecanoic acid, 2-ethyl-1-decanoic acid, 2-propyl-1-nonanoic acid, 2-butyl-1-octanoic acid and 2-pentyl-1-heptanoic acid. Certain soaps may also be included as suds suppressors.

Alkali metal sarcosinate surfactant

Other suitable anionic surfactants are the alkali metal sarcosinates of formula R--CON (R¹) CH₂ COOM, wherein R is a C₅ -C₁₇ linear or branched alkyl or alkenyl group, R¹ is a C₁ -C₄ alkyl group and M is an alkali metal ion. Preferred examples are the myristyl and oleoyl methyl sarcosinates in the form of their sodium salts.

Water-soluble builder compound

The compositions of the present invention may contain as a highly preferred component a water-soluble builder compound, typically present at a level of from 1% to 80% by weight, preferably from 10% to 70% by weight, most preferably from 20% to 60% by weight of the composition.

The detergent composition described herein has as a preferred component a water-soluble builder compound. Suitable water-soluble builder compounds include the water soluble monomeric polycarboxylates, or their acid forms, homo or copolymeric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxylic radicals separated from each other by not more that two carbon atoms, carbonates, bicarbonates, borates, phosphates, and mixtures thereof.

The carboxylate or polycarboxylate builder can be monomeric or oligomeric in type although monomeric polycarboxylates are generally preferred for reasons of cost and performance.

Suitable carboxylates containing one carboxy group include the water soluble salts of lactic acid, glycolic acid and ether derivatives thereof. Polycarboxylates containing two carboxy groups include the water-soluble salts of succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid, as well as the ether carboxylates and the sulfinyl carboxylates. Polycarboxylates containing three carboxy groups include, in particular, water-soluble citrates, aconitrates and citraconates as well as succinate derivatives such as the carboxymethyloxysuccinates described in British Patent No. 1,379,241, lactoxysuccinates described in British Patent No. 1,389,732, and aminosuccinates described in Netherlands Application 7205873, and the oxypolycarboxylate materials such as 2-oxa-1,1,3-propane tricarboxylates described in British Patent No. 1,387,447.

Polycarboxylates containing four carboxy groups include oxydisuccinates disclosed in British Patent No. 1,261,829, 1,1,2,2-ethane tetracarboxylates, 1,1,3,3-propane tetracarboxylates and 1,1,2,3-propane tetracarboxylates. Polycarboxylates containing sulfo substituents include the sulfosuccinate derivatives disclosed in British Patent Nos. 1,398,421 and 1,398,422 and in U.S. Pat. No. 3,936,448, and the sulfonated pyrolysed citrates described in British Patent No. 1,439,000.

Alicyclic and heterocyclic polycarboxylates include cyclopentane-cis,cis,cis-tetracarboxylates, cyclopentadienide pentacarboxylates, 2,3,4,5-tetrahydrofuran-cis, cis, cis-tetracarboxylates, 2,5-tetrahydrofuran-cis-dicarboxylates, 2,2,5,5-tetrahydrofuran-tetracarboxylates, 1,2,3,4,5,6-hexane-hexacarboxylates and carboxymethyl derivatives of polyhydric alcohols such as sorbitol, mannitol and xylitol. Aromatic polycarboxylates include mellitic acid, pyromellitic acid and the phthalic acid derivatives disclosed in British Patent No. 1,425,343.

Of the above, the preferred polycarboxylates are hydroxycarboxylates containing up to three carboxy groups per molecule, more particularly citrates.

The parent acids of the monomeric or oligomeric polycarboxylate chelating agents or mixtures thereof with their salts, e.g. citric acid or citrate/citric acid mixtures are also contemplated as useful builder components.

Borate builders, as well as builders containing borate-forming materials that can produce borate under detergent storage or wash conditions can also be used but are not preferred at wash conditions less that about 50° C., especially less than about 40° C.

Examples of carbonate builders are the alkaline earth and alkali metal carbonates, including sodium carbonate and sesqui-carbonate and mixtures thereof with ultra-fine calcium carbonate as disclosed in German Patent Application No. 2,321,001 published on Nov. 15, 1973.

Specific examples of water-soluble phosphate builders are the alkali metal tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium and potassium and ammonium pyrophosphate, sodium and potassium orthophosphate, sodium polymeta/phosphate in which the degree of polymerization ranges from about 6 to 21, and salts of phytic acid.

Partially soluble or insoluble builder compound

The detergent compositions of the present invention may contain a partially soluble or insoluble builder compound, typically present at a level of from 1% to 80% by weight, preferably from 10% to 70% by weight, most preferably from 20% to 60% weight of the composition.

Examples of largely water insoluble builders include the sodium aluminosilicates.

Suitable aluminosilicate zeolites have the unit cell formula Na_(z) [(AlO₂)_(z) (SiO₂)y]. xH₂ O wherein z and y are at least 6; the molar ratio of z to y is from 1.0 to 0.5 and x is at least 5, preferably from 7.5 to 276, more preferably from 10 to 264. The aluminosilicate material are in hydrated form and are preferably crystalline, containing from 10% to 28%, more preferably from 18% to 22% water in bound form.

The aluminosilicate zeolites can be naturally occurring materials, but are preferably synthetically derived. Synthetic crystalline aluminosilicate ion exchange materials are available under the designations Zeolite A, Zeolite B, Zeolite P, Zeolite X, Zeolite HS and mixtures thereof. Zeolite A has the formula

    Na.sub.12 [AlO.sub.2).sub.12 (SiO.sub.2).sub.12 ]. xH.sub.2 O

wherein x is from 20 to 30, especially 27. Zeolite X has the formula Na₈₆ [(AlO₂)₈₆ (SiO₂)₁₀₆ ]. 276H₂ O.

Amino Tricarboxylic Acid (ATCA)

The amino tricarboxylic acid (ATCA) is selected from the group having the general formula as shown below. ##STR2## where R₁, R₂ and R₃ are an alkyl group or substituted alkyl group of chain length C1 to C4, and n is 0 or 1. X is an organic substitutent group, that is a substituent typically encountered in organic compounds, but excluding X being a hydrogen substituent. X can thus for example be an alkyl, aryl, alkenyl or alkaryl group optionally substituted by any functionality including for example, amino, hydroxyl, amide and ether functionalities. X may also be an organic functional group including for example an amine, hydroxyl, amide, ester or ether group. X is preferably an alkyl group, most preferably a methyl or ethyl group. ATCA is most preferably methyl glycine diacetic acid, that is where R₁ =R₂ =a --CH--₂ group, n is 0 and X=CH₃.

ATCA can be present at levels of greater than 0.0001% by weight, preferably from 0.001% to 40% by weight, most preferably from 0.1% to 15% by weight of detergent composition.

ATCA acts as a cation complexing chelant. ATCA forms water-soluble chelates with calcium, magnesium, lead, copper, zinc, cadmium, mercury, manganese, iron, aluminium and other cationic polyvalent ions. The stability constant (measured as log K _(MeZ)) of ATCA-calcium chelate is greater than 5.0, preferably greater then 6.0. The stability constant of the preferred ATCA compound, methyl glycine diacetic acid (MGDA) is 7.0. The stability constant, log K _(MeZ) is measured in a solution of ionic strength of 0.1, at a temperature of 25° C. The figure of >5.0 for logK_(MeZ) indicates that the ratio of the concentration of the undissociated [CaATCA⁻ ] to the dissociated complex [Ca²⁺ ][ATCA³⁻ ], is >10⁵ :1

A preferred aspect of the present invention is a detergent composition containing a builder system, wherein the weight ratio of a builder to ATCA is from 5:1 to 25:1, preferably 8:1 to 20:1, most preferably 10:1 to 15:1.

Another preferred aspect of the present invention is a detergent composition containing surfactant, wherein the weight ratio of surfactant to ATCA is from 10:1 to 1:1, preferably 1:1 to 5:1, most preferably 1:1 to 3:1.

Kinetics of dissolution

The dissolution rate of the ATCA component is such that in the T50 test method described herein the time taken to achieve 50% dissolution of ATCA is less than 100 seconds, preferably less than 80 seconds, most preferably less than 60 seconds.

The ultimate wash concentration of ATCA is typically greater than 0.0001% by weight, preferably between 0.001% and 40% by weight, most preferably thereon 0.1% and 15% by weight of the wash solution.

T50 Test Method

The enhanced rate of dissolution kinetics herein are defined with respect to a `T50 test method` which measures the time to achieve 50% of the ultimate concentration/level of that component when a composition containing the component is dissolved according to the standard conditions now set out.

The standard conditions involve a 1 liter glass beaker filled with 1000 ml of distilled water at 20° C., to which 10 g of composition is added. The contents of the beaker are agitated using a magnetic stirrer set at 100 rpm. The ultimate concentration/level is taken to be the concentration/level attained 10 minutes after addition of the composition to the water-filled beaker.

Suitable analytical methods are chosen to enable a reliable determination of the incidental, and ultimate in solution concentrations of the component of concern, subsequent to the addition of the composition to the water in the beaker.

Such analytical methods can include those involving a continuous monitoring of the level of concentration of the component, including for example photometric and conductrimetric methods.

Alternatively, methods involving removing titres from the solution at set time intervals, stopping the dissolution process by an appropriate means such as by rapidly reducing the temperature of the titre, and then determining the concentration of the component in the titre by any means such as chemical tirimetric methods, can be employed.

Suitable graphical methods, including curve fitting methods, can be employed, where appropriate, to enable calculation of the TA value from raw analytical results.

The particular analytical method selected from determining the concentration of the component, will depend on the nature of that component, and of the nature of the composition containing that component.

Enhanced rate of dissolution-means

All suitable means for achieving the rate of dissolution of ATCA to the wash solution are envisaged. For example, the ATCA may be comprised in a fast release particle designed such as to provide rapid dissolution. The particle may therefore, for example, comprise a highly or even effervescently, water soluble material. Another suitable protocol could include deliberate selection of particle size of the ATCA component. The choice of particle size will depend both on the composition of the particulate component, and the desire to meet the required dissolution kinetics. It is desirable that the particle size be less than 1200 micrometers. preferably having an average particle diameter of from 1100 to 200 micrometers.

Additional protocols for providing the means of enhanced dissolution include the suitable choice of any other components of the detergent composition matrix, or of any particulate component containing ATCA such that when the composition is introduced to the wash solution the ionic strength environment herein provided enables the required enhanced dissolution kinetics to be achieved.

An alternative enhanced dissolution means can include the application of a layer of ATCA to the outermost surface of a granular or tabletted detergent composition in accord with this invention. ATCA may be applied to the granular or tabletted detergent composition by a spraying-on process.

Optional Detergent Components

The detergent composition may optionally contain various components including surfactants, bleaching agents, alkalinity sources, water-soluble builder compounds, lime soap dispersants, organic polymeric compounds including polymeric dye transfer inhibiting agents, crystal growth inhibitors, heavy metal ion sequestrants, enzymes and enzyme stabilisers, corrosion inhibitors, suds suppressors, solvents, fabric softening agents, optical brighteners and hydrotropes.

Oxygen-releasing bleaching system

An optional component of the detergent composition is an oxygen-releasing bleaching system. In one preferred aspect the bleaching system contains a hydrogen peroxide source and an organic peroxyacid bleach precursor compound. The production of the organic peroxyacid occurs by an in situ reaction of the precursor with a source of hydrogen peroxide. Preferred sources of hydrogen peroxide include inorganic perhydrate bleaches. In an alternative preferred aspect a preformed organic peroxyacid is incorporated directly into the composition. Compositions containing mixtures of a hydrogen peroxide source and organic peroxyacid precursor in combination with a preformed organic peroxyacid are also envisaged.

Inorganic perhydrate bleaches

The compositions in accord with the invention preferably include a hydrogen peroxide source, as an oxygen-releasing bleach. Suitable hydrogen peroxide sources include the inorganic perhydrate salts.

The inorganic perhydrate salts are normally incorporated in the form of the sodium salt at a level of from 1% to 40% by weight, more preferably from 2% to 30% by weight and most preferably from 5% to 25% by weight of the compositions.

Examples of inorganic perhydrate salts include perborate, percarbonate, perphosphate, persulfate and persilicate salts. The inorganic perhydrate salts are normally the alkali metal salts. The inorganic perhydrate salt may be included as the crystalline solid without additional protection. For certain perhydrate salts however, the preferred executions of such granular compositions utilize a coated form of the material which provides better storage stability for the perhydrate salt in the granular product.

Sodium perborate can be in the form of the monohydrate of nominal formula NaBO₂ H₂ O₂ or the tetrahydrate NaBO₂ H₂ O₂.3H₂ O.

Alkali metal percarbonates, particularly sodium percarbonate are preferred perhydrates for inclusion in compositions in accordance with the invention. Sodium percarbonate is an addition compound having a formula corresponding to 2Na₂ CO₃.3H₂ O₂, and is available commercially as a crystalline solid. Sodium percarbonate, being a hydrogen peroxide addition compound tends on dissolution to release the hydrogen peroxide quite rapidly which can increase the tendency for localised high bleach concentrations to arise. The percarbonate is most preferably incorporated into such compositions in a coated form which provides in-product stability.

A suitable coating material providing in product stability comprises mixed salt of a water soluble alkali metal sulphate and carbonate. Such coatings together with coating processes have previously been described in GB-1,466,799, granted to Interox on Mar. 9, 1977. The weight ratio of the mixed salt coating material to percarbonate lies in the range from 1:200 to 1:4, more preferably from 1:99 to 1:9, and most preferably from 1:49 to 1:19. Preferably, the mixed salt is of sodium sulphate and sodium carbonate which has the general formula Na₂ SO₄.n.Na₂ CO₃ wherein n is from 0.1 to 3, preferably n is from 0.3 to 1.0 and most preferably n is from 0.2 to 0.5.

Other coatings which contain silicate (alone or with borate salts or boric acids or other inorganics), waxes, oils, fatty soaps can also be used advantageously within the present invention.

Potassium peroxymonopersulfate is another inorganic perhydrate salt of utility in the compositions herein.

Peroxyacid bleach precursor

Peroxyacid bleach precursors are compounds which react with hydrogen peroxide in a perhydrolysis reaction to produce a peroxyacid. Generally peroxyacid bleach precursors may be represented as ##STR3## where L is a leaving group and X is essentially any functionality, such that on perhydrolysis the structure of the peroxyacid produced is ##STR4##

Peroxyacid bleach precursor compounds are preferably incorporated at a level of from 0.5% to 20% by weight, more preferably from 1% to 10% by weight, most preferably from 1.5% to 5% by weight of the compositions.

Suitable peroxyacid bleach precursor compounds typically contain one or more N- or O-acyl groups, which precursors can be selected from a wide range of classes. Suitable classes include anhydrides, esters, imides, lactams and acylated derivatives of imidazoles and oximes. Examples of useful materials within these classes are disclosed in GB-A-1586789. Suitable esters are disclosed in GB-A-836988, 864798, 1147871, 2143231 and EP-A-0170386.

Leaving groups

The leaving group, hereinafter L group, must be sufficiently reactive for the perhydrolysis reaction to occur within the optimum time frame (e.g., a wash cycle). However, if L is too reactive, this activator will be difficult to stabilize for use in a bleaching composition.

Preferred L groups are selected from the group consisting of: ##STR5## and mixtures thereof, wherein R¹ is an alkyl, aryl, or alkaryl group containing from 1 to 14 carbon atoms, R³ is an alkyl chain containing from 1 to 8 carbon atoms, R⁴ is H or R³, and Y is H or a solubilizing group. Any of R¹, R³ and R⁴ may be substituted by essentially any functional group including, for example alkyl, hydroxy, alkoxy, halogen, amine, nitrosyl, amide and ammonium or alkyl ammonium groups.

The preferred solubilizing groups are --SO₃ ⁻ M⁺, --CO₂ ⁻ M⁺, --SO₄ ⁻ M⁺, --N⁺ (R³)₄ X⁻ and O←N(R³)₃ and most preferably --SO₃ ⁻ M⁺ and --CO₂ ⁻ M⁺ wherein R³ is an alkyl chain containing from 1 to 4 carbon atoms, M is a cation which provides solubility to the bleach activator and X is an anion which provides solubility to the bleach activator. Preferably, M is an alkali metal, ammonium or substituted ammonium cation, with sodium and potassium being most preferred, and X is a halide, hydroxide, methylsulfate or acetate anion.

Perbenzoic acid precursor

Perbenzoic acid precursor compounds provide perbenzoic acid on perhydrolysis.

Suitable O-acylated perbenzoic acid precursor compounds include the substituted and unsubstituted benzoyl oxybenzene sulfonates, including for example benzoyl oxybenzene sulfonate: ##STR6## Also suitable are the benzoylation products of sorbitol, glucose, and all saccharides with benzoylating agents, including for example: ##STR7## Perbenzoic acid precursor compounds of the imide type include N-benzoyl succinimide, tetrabenzoyl ethylene diamine and the N-benzoyl substituted ureas. Suitable imidazole type perbenzoic acid precursors include N-benzoyl imidazole and N-benzoyl benzimidazole and other useful N-acyl group-containing perbenzoic acid precursors include N-benzoyl pyrrolidone, dibenzoyl taurine and benzoyl pyroglutamic acid.

Other perbenzoic acid precursors include the benzoyl diacyl peroxides, the benzoyl tetraacyl peroxides, and the compound having the formula: ##STR8## Phthalic anhydride is another suitable perbenzoic acid precursor compound herein: ##STR9## Suitable N-acylated lactam perbenzoic acid precursors have the formula: ##STR10## wherein n is from 0 to 8, preferably from 0 to 2, and R⁶ is a benzoyl group.

Perbenzoic acid derivative precursors

Perbenzoic acid derivative precursors provide substituted perbenzoic acids on perhydrolysis.

Suitable substituted perbenzoic acid derivative precursors include any of the herein disclosed perbenzoic precursors in which the benzoyl group is substituted by essentially any non-positively charged (i.e.; non-cationic) functional group including, for example alkyl, hydroxy, alkoxy, halogen, amine, nitrosyl and amide groups.

A preferred class of substituted perbenzoic acid precursor compounds are the amide substituted compounds of the following general formulae: ##STR11## wherein R¹ is an aryl or alkaryl group with from 1 to 14 carbon atoms, R² is an arylene, or alkarylene group containing from 1 to 14 carbon atoms, and R⁵ is H or an alkyl, aryl, or alkaryl group containing 1 to 10 carbon atoms and L can be essentially any leaving group. R¹ preferably contains from 6 to 12 carbon atoms. R² preferably contains from 4 to 8 carbon atoms. R¹ may be aryl, substituted aryl or alkylaryl containing branching, substitution, or both and may be sourced from either synthetic sources or natural sources including for example, tallow fat. Analogous structural variations are permissible for R². The substitution can include alkyl, aryl, halogen, nitrogen, sulphur and other typical substituent groups or organic compounds. R⁵ is preferably H or methyl. R¹ and R⁵ should not contain more than 18 carbon atoms in total. Amide substituted bleach activator compounds of this type are described in EP-A-0170386.

Cationic peroxyacid precursors

Cationic peroxyacid precursor compounds produce cationic peroxyacids on perhydrolysis.

Typically, cationic peroxyacid precursors are formed by substituting the peroxyacid part of a suitable peroxyacid precursor compound with a positively charged functional group, such as an ammonium or alkyl ammonium group, preferably an ethyl or methyl ammonium group. Cationic peroxyacid precursors are typically present in the compositions as a salt with a suitable anion, such as for example a halide ion or a methylsulfate ion.

The peroxyacid precursor compound to be so cationically substituted may be a perbenzoic acid, or substituted derivative thereof, precursor compound as described hereinbefore. Alternatively, the peroxyacid precursor compound may be an alkyl percarboxylic acid precursor compound or an amide substituted alkyl peroxyacid precursor as described hereinafter

Cationic peroxyacid precursors are described in U.S. Pat. Nos. 4,904,406; 4,751,015; 4,988,451; 4,397,757; 5,269,962; 5,127,852; 5,093,022; 5,106,528; U.K. 1,382,594; EP 475,512, 458,396 and 284,292; and in JP 87-318,332.

Suitable cationic peroxyacid precursors include any of the ammonium or alkyl ammonium substituted alkyl or benzoyl oxybenzene sulfonates, N-acylated caprolactams, and monobenzoyltetraacetyl glucose benzoyl peroxides.

A preferred cationically substituted benzoyl oxybenzene sulfonate is the 4-(trimethyl ammonium) methyl derivative of benzoyl oxybenzene sulfonate: ##STR12## A preferred cationically substituted alkyl oxybenzene sulfonate has the formula: ##STR13## Preferred cationic peroxyacid precursors of the N-acylated caprolactam class include the trialkyl ammonium methylene benzoyl caprolactams, particularly trimethyl ammonium methylene benzoyl caprolactam: ##STR14## Other preferred cationic peroxyacid precursors of the N-acylated caprolactam class include the trialkyl ammonium methylene alkyl caprolactams: ##STR15## where n is from 0 to 12, particularly from 1 to 5.

Another preferred cationic peroxyacid precursor is 2-(N,N,N-trimethyl ammonium) ethyl sodium 4-sulphophenyl carbonate chloride.

Alkyl percarboxylic acid bleach precursors

Alkyl percarboxylic acid bleach precursors form percarboxylic acids on perhydrolysis. Preferred precursors of this type provide peracetic acid on perhydrolysis.

Preferred alkyl percarboxylic precursor compounds of the imide type include the N--,N,N¹ N¹ tetra acetylated alkylene diamines wherein the alkylene group contains from 1 to 6 carbon atoms, particularly those compounds in which the alkylene group contains 1, 2 and 6 carbon atoms. Tetraacetyl ethylene diamine (TAED) is particularly preferred.

Other preferred alkyl percarboxylic acid precursors include sodium 3,5,5-tri-methyl hexanoyloxybenzene sulfonate (iso-NOBS), sodium nonanoyloxybenzene sulfonate (NOBS), sodium acetoxybenzene sulfonate (ABS) and penta acetyl glucose.

Amide substituted alkyl peroxyacid precursors

Amide substituted alkyl peroxyacid precursor compounds are also suitable, including those of the following general formulae: ##STR16## wherein R¹ is an alkyl group with from 1 to 14 carbon atoms, R² is an alkylene group containing from 1 to 14 carbon atoms, and R⁵ is H or an alkyl group containing 1 to 10 carbon atoms and L can be essentially any leaving group. R¹ preferably contains from 6 to 12 carbon atoms. R² preferably contains from 4 to 8 carbon atoms. R¹ may be straight chain or branched alkyl containing branching, substitution, or both and may be sourced from either synthetic sources or natural sources including for example, tallow fat. Analogous structural variations are permissible for R². The substitution can include alkyl, halogen, nitrogen, sulphur and other typical substituent groups or organic compounds. R⁵ is preferably H or methyl. R¹ and R⁵ should not contain more than 18 carbon atoms in total. Amide substituted bleach activator compounds of this type are described in EP-A-0170386.

Benzoxazin organic peroxyacid precursors

Also suitable are precursor compounds of the benzoxazin-type, as disclosed for example in EP-A-332,294 and EP-A-482,807, particularly those having the formula: ##STR17## including the substituted benzoxazins of the type ##STR18## wherein R₁ is H, alkyl, alkaryl, aryl, arylalkyl, and wherein R₂, R₃, R₄, and R₅ may be the same or different substituents selected from H, halogen, alkyl, alkenyl, aryl, hydroxyl, alkoxyl, amino, alkyl amino, COOR₆ (wherein R₆ is H or an alkyl group) and carbonyl functions.

An especially preferred precursor of the benzoxazin-type is: ##STR19## Preformed organic peroxyacid

The organic peroxyacid bleaching system may contain, in addition to, or as an alternative to, an organic peroxyacid bleach precursor compound, a preformed organic peroxyacid, typically at a level of from 0.5% to 25% by weight, more preferably from 1% to 10% by weight of the composition.

A preferred class of organic peroxyacid compounds are the amide substituted compounds of the following general formulae: ##STR20## wherein R¹ is an alkyl, aryl or alkaryl group with from 1 to 14 carbon atoms, R² is an alkylene, arylene, and alkarylene group containing from 1 to 14 carbon atoms, and R⁵ is H or an alkyl, aryl, or alkaryl group containing 1 to 10 carbon atoms. R¹ preferably contains from 6 to 12 carbon atoms. R² preferably contains from 4 to 8 carbon atoms. R¹ may be straight chain or branched alkyl, substituted aryl or alkylaryl containing branching, substitution, or both and may be sourced from either synthetic sources or natural sources including for example, tallow fat. Analogous structural variations are permissible for R². The substitution can include alkyl, aryl, halogen, nitrogen, sulphur and other typical substituent groups or organic compounds. R⁵ is preferably H or methyl. R¹ and R⁵ should not contain more than 18 carbon atoms in total. Amide substituted organic peroxyacid compounds of this type are described in EP-A-0170386.

Other organic peroxyacids include diacyl and tetraacylperoxides, especially diperoxydodecanedioc acid, diperoxytetradecanedioc acid, and diperoxyhexadecanedioc acid. Dibenzoyl peroxide is a preferred organic peroxyacid herein. Mono- and diperazelaic acid, mono- and diperbrassylic acid, and N-phthaloylaminoperoxicaproic acid are also suitable herein.

Water-soluble bismuth compound

The compositions used in this invention may contain a water-soluble bismuth compound, preferably present at a level of from 0.005% to 20%, more preferably from 0.01% to 5%, most preferably from 0.1% to 1% by weight of the compositions.

The water-soluble bismuth compound may be essentially any salt or complex of bismuth with essentially any inorganic or organic counter anion. Preferred inorganic bismuth salts are selected from the bismuth trihalides, bismuth nitrate and bismuth phosphate. Bismuth acetate and citrate are preferred salts with an organic counter anion.

Water-soluble sulfate salt

The compositions may optionally contain a water-soluble sulfate salt, preferably present at a level of from 0.1% to 40%, more preferably from 1% to 30%, most preferably from 5% to 25% by weight of the compositions.

The water-soluble sulfate salt may be essentially any salt of sulfate with any counter cation. Preferred salts are selected from the sulfates of the alkali and alkaline earth metals, particularly sodium sulfate.

Corrosion inhibitor compound

The compositions may contain corrosion inhibitors preferably selected from organic silver coating agents, particularly paraffin, nitrogen-containing corrosion inhibitor compounds and Mn(II) compounds, particularly Mn(II) salts of organic ligands.

Organic silver coating agents are described in PCT Publication No. WO94/16047 and copending UK Application No. UK 9413729.6. Nitrogen-containing corrosion inhibitor compounds are disclosed in copending European Application no. EP 93202095.1. Mn(II) compounds for use in corrosion inhibition are described in copending UK Application No. 9418567.5.

Organic silver coating agents

Organic silver coating agent may be incorporated at a level of from 0.05% to 10%, preferably from 0.1% to 5% by weight of the total composition.

The functional role of the silver coating agent is to form `in use` a protective coating layer on any silverware components of the washload to which the compositions of the invention are being applied. The silver coating agent should hence have a high affinity for attachment to solid silver surfaces, particularly when present in as a component of an aqueous washing and bleaching solution with which the solid silver surfaces are being treated.

Suitable organic silver coating agents herein include fatty esters of mono- or polyhydric alcohols having from 1 to about 40 carbon atoms in the hydrocarbon chain.

The fatty acid portion of the fatty ester can be obtained from mono- or poly-carboxylic acids having from 1 to about 40 carbon atoms in the hydrocarbon chain. Suitable examples of monocarboxylic fatty acids include behenic acid, stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, acetic acid, propionic acid, butyric acid, isobutyric acid, Valerie acid, lactic acid, glycolic acid and β,β'-dihydroxyisobutyric acid. Examples of suitable polycarboxylic acids include: n-butyl-malonic acid, isocitric acid, citric acid, maleic acid, malic acid and succinic acid.

The fatty alcohol radical in the fatty ester can be represented by mono- or polyhydric alcohols having from 1 to 40 carbon atoms in the hydrocarbon chain. Examples of suitable fatty alcohols include; behenyl, arachidyl, cocoyl, oleyl and lauryl alcohol, ethylene glycol, glycerol, ethanol, isopropanol, vinyl alcohol, diglycerol, xylitol, sucrose, erythritol, pentaerythritol, sorbitol or sorbitan.

Preferably, the fatty acid and/or fatty alcohol group of the fatty ester adjunct material have from 1 to 24 carbon atoms in the alkyl chain.

Preferred fatty esters herein are ethylene glycol, glycerol and sorbitan esters wherein the fatty acid portion of the ester normally comprises a species selected from behenic acid, stearic acid, oleic acid, palmitic acid or myristic acid.

The glycerol esters are also highly preferred. These are the mono-, di- or tri-esters of glycerol and the fatty acids as defined above.

Specific examples of fatty alcohol esters for use herein include: stearyl acetate, palmityl di-lactate, cocoyl isobutyrate, oleyl maleate, oleyl dimaleate, and tallowyl proprionate. Fatty acid esters useful herein include: xylitol monopalmitate, pentaerythritol monostearate, sucrose monostearate, glycerol monostearate, ethylene glycol monostearate, sorbitan esters. Suitable sorbitan esters include sorbitan monostearate, sorbitan palmitate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monobehenate, sorbitan mono-oleate, sorbitan dilaurate, sorbitan distearate, sorbitan dibehenate, sorbitan dioleate, and also mixed tallowalkyl sorbitan mono- and di-esters.

Glycerol monostearate, glycerol mono-oleate, glycerol monopalmitate, glycerol monobehenate, and glycerol distearate are preferred glycerol esters herein.

Suitable organic silver coating agents include triglycerides, mono or diglycerides, and wholly or partially hydrogenated derivatives thereof, and any mixtures thereof. Suitable sources of fatty acid esters include vegetable and fish oils and animal fats. Suitable vegetable oils include soy bean oil, cotton seed oil, castor oil, olive oil, peanut oil, safflower oil, sunflower oil, rapeseed oil, grapeseed oil, palm oil and corn oil.

Waxes, including microcrystalline waxes are suitable organic silver coating agents herein. Preferred waxes have a melting point in the range from about 35° C. to about 110° C. and comprise generally from 12 to 70 carbon atoms. Preferred are petroleum waxes of the paraffin and microcrystalline type which are composed of long-chain saturated hydrocarbon compounds.

Alginates and gelatin are suitable organic silver coating agents herein.

Dialkyl amine oxides such as C₁₂ -C₂₀ methylamine oxide, and dialkyl quaternary ammonium compounds and salts, such as the C₁₂ -C₂₀ methylammonium halides are also suitable.

Other suitable organic silver coating agents include certain polymeric materials. Polyvinylpyrrolidones with an average molecular weight of from 12,000 to 700,000, polyethylene glycols (PEG) with an average molecular weight of from 600 to 10,000, polyamine N-oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, and cellulose derivatives such as methylcellulose, carboxymethylcellulose and hydroxyethylcellulose are examples of such polymeric materials.

Certain perfume materials, particularly those demonstrating a high substantivity for metallic surfaces, are also useful as the organic silver coating agents herein.

Polymeric soil release agents can also be used as an organic silver coating agent.

Suitable polymeric soil release agents include those soil release agents having: (a) one or more nonionic hydrophile components consisting essentially of (i) polyoxyethylene segments with a degree of polymerization of at least 2, or (ii) oxypropylene or polyoxypropylene segments with a degree of polymerization of from 2 to 10, wherein said hydrophile segment does not encompass any oxypropylene unit unless it is bonded to adjacent moieties at each end by ether linkages, or (iii) a mixture of oxyalkylene units comprising oxyethylene and from 1 to about 30 oxypropylene units, said hydrophile segments preferably comprising at least about 25% oxyethylene units and more preferably, especially for such components having about 20 to 30 oxypropylene units, at least about 50% oxyethylene units; or (b) one or more hydrophobe components comprising (i) C₃ oxyalkylene terephthalate segments, wherein, if said hydrophobe components also comprise oxyethylene terephthalate, the ratio of oxyethylene terephthalate:C₃ oxyalkylene terephthalate units is about 2:1 or lower, (ii) C₄ -C₆ alkylene or oxy C₄ -C₆ alkylene segments, or mixtures therein, (iii) poly (vinyl ester) segments, preferably polyvinyl acetate, having a degree of polymerization of at least 2, or (iv) C₁ -C₄ alkyl ether or C₄ hydroxyalkyl ether substituents, or mixtures therein, wherein said substituents are present in the form of C₁ -C₄ alkyl ether or C₄ hydroxyalkyl ether cellulose derivatives, or mixtures therein, or a combination of (a) and (b).

Typically, the polyoxyethylene segments of (a)(i) will have a degree of polymerization of from about 200, although higher levels can be used, preferably from 3 to about 150, more preferably from 6 to about 100. Suitable oxy C₄ -C₆ alkylene hydrophobe segments include, but are not limited to, end-caps of polymeric soil release agents such as MO₃ S(CH₂)_(n) OCH₂ CH₂ O--, where M is sodium and n is an integer from 4-6, as disclosed in U.S. Pat. No. 4,721,580, issued Jan. 26, 1988 to Gosselink.

Polymeric soil release agents useful herein also include cellulosic derivatives such as hydroxyether cellulosic polymers, copolymeric blocks of ethylene terephthalate or propylene terephthalate with polyethylene oxide or polypropylene oxide terephthalate, and the like. Such agents are commercially available and include hydroxyethers of cellulose such as METHOCEL (Dow). Cellulosic soil release agents for use herein also include those selected from the group consisting of C₁ -C₄ alkyl and C₄ hydroxyalkyl cellulose; see U.S. Pat. No. 4,000,093, issued Dec. 28, 1976 to Nicol, et al.

Soil release agents characterized by poly(vinyl ester) hydrophobe segments include graft copolymers of poly(vinyl ester), e.g., C₁ -C₆ vinyl esters, preferably poly(vinyl acetate) grafted onto polyalkylene oxide backbones, such as polyethylene oxide backbones. See European Patent Application 0 219 048, published Apr. 22, 1987 by Kud, et al.

Another suitable soil release agent is a copolymer having random blocks of ethylene terephthalate and polyethylene oxide (PEO) terephthalate. The molecular weight of this polymeric soil release agent is in the range of from about 25,000 to about 55,000. See U.S. Pat. No. 3,959,230 to Hays, issued May 25, 1976 and U.S. Pat. No. 3,893,929 to Basadur issued Jul. 8, 1975.

Another suitable polymeric soil release agent is a polyester with repeat units of ethylene terephthalate units contains 10-15% by weight of ethylene terephthalate units together with 90-80% by weight of polyoxyethylene terephthalate units, derived from a polyoxyethylene glycol of average molecular weight 300-5,000.

Another suitable polymeric soil release agent is a sulfonated product of a substantially linear ester oligomer comprised of an oligomeric ester backbone of terephthaloyl and oxyalkyleneoxy repeat units and terminal moieties covalently attached to the backbone. These soil release agents are described fully in U.S. Pat. No. 4,968,451, issued Nov. 6, 1990 to J. J. Scheibel and E. P. Gosselink. Other suitable polymeric soil release agents include the terephthalate polyesters of U.S. Pat. No. 4,711,730, issued Dec. 8, 1987 to Gosselink et al, the anionic end-capped oligomeric esters of U.S. Pat. No. 4,721,580, issued Jan. 26, 1988 to Gosselink, and the block polyester oligomeric compounds of U.S. Pat. No. 4,702,857, issued Oct. 27, 1987 to Gosselink. Other polymeric soil release agents also include the soil release agents of U.S. Pat. No. 4,877,896, issued Oct. 31, 1989 to Maldonado et al, which discloses anionic, especially sulfoarolyl, end-capped terephthalate esters.

Another soil release agent is an oligomer with repeat units of terephthaloyl units, sulfoisoterephthaloyl units, oxyethyleneoxy and oxy-1,2-propylene units. The repeat units form the backbone of the oligomer and are preferably terminated with modified isethionate end-caps. A particularly preferred soil release agent of this type comprises about one sulfoisophthaloyl unit, 5 terephthaloyl units, oxyethyleneoxy and oxy-1,2-propyleneoxy units in a ratio of from about 1.7 to about 1.8, and two end-cap units of sodium 2-(2-hydroxyethoxy)-ethanesulfonate.

A preferred organic silver coating agent is a paraffin oil, typically a predominantly branched aliphatic hydrocarbon having a number of carbon atoms in the range of from 20 to 50; preferred paraffin oil selected from predominantly branched C₂₅₋₄₅ species with a ratio of cyclic to noncyclic hydrocarbons of from 1:10 to 2:1, preferably from 1:5 to 1:1. A paraffin oil meeting these characteristics, having a ratio of cyclic to noncyclic hydrocarbons of about 32:68, is sold by Wintershall, Salzbergen, Germany, under the trade name WINOG 70.

Nitrogen-containing corrosion inhibitor compounds

Suitable nitrogen-containing corrosion inhibitor compounds include imidazole and derivatives thereof such as benzimidazole, 2-heptadecyl imidazole and those imidazole derivatives described in Czech Patent No. 139, 279 and British Patent GB-A-1,137,741, which also discloses a method for making imidazole compounds.

Also suitable as nitrogen-containing corrosion inhibitor compounds are pyrazole compounds and their derivatives, particularly those where the pyrazole is substituted in any of the 1, 3, 4 or 5 positions by substituents R₁, R₃, R₄ and R₅ where R₁ is any of H, CH₂ OH, CONH₃, or COCH₃, R₃ and R₅ are any of C₁ -C₂₀ alkyl or hydroxyl, and R₄ is any of H, NH₂ or NO₂.

Other suitable nitrogen-containing corrosion inhibitor compounds include benzotriazole, 2-mercaptobenzothiazole, 1-phenyl-5-mercapto-1,2,3,4-tetrazole, thionalide, morpholine, melamine, distearylamine, stearoyl stearamide, cyanuric acid, aminotriazole, aminotetrazole and indazole.

Nitrogen-containing compounds such as amines, especially distearylamine and ammonium compounds such as ammonium chloride, ammonium bromide, ammonium sulphate or diammonium hydrogen citrate are also suitable.

Mn(II) corrosion inhibitor compounds

The compositions may contain an Mn(II) corrosion inhibitor compound. The Mn(II) compound is preferably incorporated at a level of from 0.005% to 5% by weight, more preferably from 0.01% to 1%, most preferably from 0.02% to 0.4% by weight of the compositions. Preferably, the Mn(II) compound is incorporated at a level to provide from 0.1 ppm to 250 ppm, more preferably from 0.5 ppm to 50 ppm, most preferably from 1 ppm to 20 ppm by weight of Mn(II) ions in any bleaching solution.

The Mn (II) compound may be an inorganic salt in anhydrous, or any hydrated forms. Suitable salts include manganese sulphate, manganese carbonate, manganese phosphate, manganese nitrate, manganese acetate and manganese chloride. The Mn(II) compound may be a salt or complex of an organic fatty acid such as manganese acetate or manganese stearate.

The Mn(II) compound may be a salt or complex of an organic ligand. In one preferred aspect the organic ligand is a heavy metal ion sequestrant. In another preferred aspect the organic ligand is a crystal growth inhibitor.

Other corrosion inhibitor compounds

Other suitable additional corrosion inhibitor compounds include, mercaptans and diols, especially mercaptans with 4 to 20 carbon atoms including lauryl mercaptan, thiophenol, thionapthol, thionalide and thioanthranol. Also suitable are saturated or unsaturated C₁₀ -C₂₀ fatty acids, or their salts, especially aluminium tristearate. The C₁₂ -C₂₀ hydroxy fatty acids, or their salts, are also suitable. Phosphonated octadecane and other anti-oxidants such as betahydroxytoluene (BHT) are also suitable.

Copolymers of butadiene and maleic acid, particularly those supplied under the trade reference no. 07787 by Polysciences Inc have been found to be of particular utility as corrosion inhibitor compounds.

Total Available Oxygen (AvO) Level

It has been found that, for optimal anti-silver tarnishing performance, the level of available oxygen in the present compositions, measured in units of % available oxygen by weight of the composition, is preferably controlled; the level of available oxygen should hence preferably be in the range from 0.3% to 2.5%, preferably from 0.5% to 1.7%, more preferably from 0.6% to 1.5%, most preferably from 0.7% to 1.2%, measured according to the method described hereunder.

Rate of Release of AvO

The rate of release of available oxygen is preferably also controlled; the rate of release of available oxygen from the compositions herein preferably should be such that, when using the method described hereinafter, the available oxygen is not completely released from the composition until after 3.5 minutes, preferably the available oxygen is released in a time interval of from 3.5 minutes to 10.0 minutes, more preferably from 4.0 minutes to 9.0 minutes, most preferably from 5.0 minutes to 8.5 minutes.

Method for Measuring Level of Total Available Oxygen (AvO) and Rate of Release of AvO in a Detergent Composition

Method

1. A beaker of water (typically 2 L) is placed on a stirrer Hotplate, and the stirrer speed is selected to ensure that the product is evenly dispersed through the solution.

2. The detergent composition (typically 8 g of product which has been sampled down from a bulk supply using a Pascal sampler), is added and simultaneously a stop clock is started.

3. The temperature control should be adjusted so as to maintain a constant temperature of 20° C. throughout the experiment.

4. Samples are taken from the detergent solution at 2 minute time intervals for 20 minutes, starting after 1 minute, and are titrated by the "titration procedure" described below to determine the level of available oxygen at each point.

Titration Procedure

1. An aliquot from the detergent solution (above) and 2 ml sulphuric acid are added into a stirred beaker

2. Approximately 0.2 g ammonium molybdate catalyst (tetra hydrate form) are added

3. 3 mls of 10% sodium iodide solution are added

4. Titration with sodium thiosulphate is conducted until the end point. The end point can be seen using either of two procedures. First procedure consists simply in seeing the yellow iodine colour fading to clear. The second and preferred procedure consists of adding soluble starch when the yellow colour is becoming faint, turning the solution blue. More thiosulphate is added until the end point is reached (blue starch complex is decolourised).

The level of AvO, measured in units of % available oxygen by weight, for the sample at each time interval corresponds to the amount of titre according to the following equation ##EQU1## AvO level is plotted versus time to determine the maximum level of AvO, and the rate of release of AvO

Controlled rate of release-means

A means may be provided for controlling the rate of release of oxygen bleach to the wash solution.

Means for controlling the rate of release of the bleach may provide for controlled release of peroxide species to the wash solution. Such means could, for example, include controlling the release of any inorganic perhydrate salt, acting as a hydrogen peroxide source, to the wash solution.

Suitable controlled release means can include coating any suitable component with a coating designed to provide the controlled release. The coating may therefore, for example, comprise a poorly water soluble material, or be a coating of sufficient thickness that the kinetics of dissolution of the thick coating provide the controlled rate of release.

The coating material may be applied using various methods. Any coating material is typically present at a weight ratio of coating material to bleach of from 1:99 to 1:2, preferably from 1:49 to 1:9.

Suitable coating materials include triglycerides (e.g. partially) hydrogenated vegetable oil, soy bean oil, cotton seed oil) mono or diglycerides, microcrystalline waxes, gelatin, cellulose, fatty acids and any mixtures thereof.

Other suitable coating materials can comprise the alkali and alkaline earth metal sulphates, silicates and carbonates, including calcium carbonate and silicas.

A preferred coating material, particularly for an inorganic perhydrate salt bleach source, comprises sodium silicate of SiO₂ :Na₂ O ratio from 1.8:1 to 3.0:1, preferably 1.8:1 to 2.4:1, and/or sodium metasilicate, preferably applied at a level of from 2% to 10%, (normally from 3% to 5%) of SiO₂ by weight of the inorganic perhydrate salt. Magnesium silicate can also be included in the coating.

Any inorganic salt coating materials may be combined with organic binder materials to provide composite inorganic salt/organic binder coatings. Suitable binders include the C₁₀ -C₂₀ alcohol ethoxylates containing from 5-100 moles of ethylene oxide per mole of alcohol and more preferably the C₁₅ -C₂₀ primary alcohol ethoxylates containing from 20-100 moles of ethylene oxide per mole of alcohol.

Other preferred binders include certain polymeric materials. Polyvinylpyrrolidones with an average molecular weight of from 12,000 to 700,000 and polyethylene glycols (PEG) with an average molecular weight of from 600 to 5×10⁶ preferably 1000 to 400,000 most preferably 1000 to 10,000 are examples of such polymeric materials. Copolymers of maleic anhydride with ethylene, methylvinyl ether or methacrylic acid, the maleic anhydride constituting at least 20 mole percent of the polymer are further examples of polymeric materials useful as binder agents. These polymeric materials may be used as such or in combination with solvents such as water, propylene glycol and the above mentioned C₁₀ -C₂₀ alcohol ethoxylates containing from 5-100 moles of ethylene oxide per mole. Further examples of binders include the C₁₀ -C₂₀ mono- and diglycerol ethers and also the C₁₀ -C₂₀ fatty acids.

Cellulose derivatives such as methylcellulose, carboxymethylcellulose and hydroxyethylcellulose, and homo- or co-polymeric polycarboxylic acids or their salts are other examples of binders suitable for use herein.

One method for applying the coating material involves agglomeration. Preferred agglomeration processes include the use of any of the organic binder materials described hereinabove. Any conventional agglomerator/mixer may be used including, but not limited to pan, rotary drum and vertical blender types. Molten coating compositions may also be applied either by being poured onto, or spray atomized onto a moving bed of bleaching agent.

Other means of providing the required controlled release include mechanical means for altering the physical characteristics of the bleach to control its solubility and rate of release. Suitable protocols could include compaction, mechanical injection, manual injection, and adjustment of the solubility of the bleach compound by selection of particle size of any particulate component.

Whilst the choice of particle size will depend both on the composition of the particulate component, and the desire to meet the desired controlled release kinetics, it is desirable that the particle size should be more than 500 micrometers, preferably having an average particle diameter of from 800 to 1200 micrometers.

Additional protocols for providing the means of controlled release include the suitable choice of any other components of the detergent composition matrix such that when the composition is introduced to the wash solution the ionic strength environment therein provided enables the required controlled release kinetics to be achieved.

Alkalinity system

The compositions preferably contain an alkalinity system containing sodium silicate having an SiO₂ :Na₂ O ratio of from 1.8 to 3.0, preferably from 1.8 to 2.4, most preferably 2.0, present preferably at a level of less than 20%, preferably from 1% to 15%, most preferably from 3% to 12% by weight of SiO₂. The alkali metal silicate may be in the form of either the anhydrous salt or a hydrated salt.

The alkalinity system also preferably contains sodium metasilicate, present at a level of at least 0.4% SiO₂ by weight. Sodium metasilicate has a nominal SiO₂ :Na₂ O ratio of 1.0. The weight ratio of said sodium silicate to said sodium metasilicate, measured as SiO₂, is preferably from 50:1 to 5:4, more preferably from 15:1 to 2:1, most preferably from 10:1 to 5:2.

Heavy metal ion sequestrant

The detergent compositions of the invention preferably contain as an optional component a heavy metal ion sequestrant. By heavy metal ion sequestrant it is meant herein components which act to sequester (chelate) heavy metal ions. These components may also have calcium and magnesium chelation capacity, but preferentially they show selectivity to binding heavy metal ions such as iron, manganese and copper.

Heavy metal ion sequestrants are generally present at a level of from 0.005% to 20%, preferably from 0.1% to 10%, more preferably from 0.25% to 7.5% and most preferably from 0.5% to 5% by weight of the compositions.

Heavy metal ion sequestrants, which are acidic in nature, having for example phosphonic acid or carboxylic acid functionalities, may be present either in their acid form or as a complex/salt with a suitable counter cation such as an alkali or alkaline metal ion, ammonium, or substituted ammonium ion, or any mixtures thereof. Preferably any salts/complexes are water soluble. The molar ratio of said counter cation to the heavy metal ion sequestrant is preferably at least 1:1.

Suitable heavy metal ion sequestrants for use herein include organic phosphonates, such as the amino alkylene poly (alkylene phosphonates), alkali metal ethane 1-hydroxy disphosphonates and nitrilo trimethylene phosphonates. Preferred among the above species are diethylene triamine penta (methylene phosphonate), ethylene diamine tri (methylene phosphonate) hexamethylene diamine tetra (methylene phosphonate) and hydroxy-ethylene 1,1 diphosphonate.

Other suitable heavy metal ion sequestrant for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, ethylenediamine disuccinic acid, ethylenediamine diglutaric acid, 2-hydroxypropylenediamine disuccinic acid or any salts thereof.

Especially preferred is ethylenediamine-N,N'-disuccinic acid (EDDS) or the alkali metal, alkaline earth metal, ammonium, or substituted ammonium salts thereof, or mixtures thereof. Preferred EDDS compounds are the free acid form and the sodium or magnesium salt or complex thereof.

Crystal growth inhibitor component

The detergent compositions preferably contain a crystal growth inhibitor component, preferably an organodiphosphonic acid component, incorporated preferably at a level of from 0.01% to 5%, more preferably from 0.1% to 2% by weight of the compositions.

By organo diphosphonic acid it is meant herein an organo diphosphonic acid which does not contain nitrogen as part of its chemical structure. This definition therefore excludes the organo aminophosphonates, which however may be included in compositions of the invention as heavy metal ion sequestrant components.

The organo diphosphonic acid is preferably a C₁ -C₄ diphosphonic acid, more preferably a C₂ diphosphonic acid, such as ethylene diphosphonic acid, or most preferably ethane 1-hydroxy-1,1-diphosphonic acid (HEDP) and may be present in partially or fully ionized form, particularly as a salt or complex.

Enzyme

Another optional ingredient useful in the compositions is one or more enzymes. Preferred enzymatic materials include the commercially available lipases, amylases, neutral and alkaline proteases, esterases, cellulases, pectinases, lactases and peroxidases conventionally incorporated into detergent compositions. Suitable enzymes are discussed in U.S. Pat. Nos. 3,519,570 and 3,533,139.

Preferred commercially available protease enzymes include those sold under the tradenames Alcalase, Savinase, Primase, Durazym, and Esperase by Novo Industries A/S (Denmark), those sold under the tradename Maxatase, Maxacal and Maxapem by Gist-Brocades, those sold by Genencor International, and those sold under the tradename Opticlean and Optimase by Solvay Enzymes. Protease enzyme may be incorporated into the compositions in accordance with the invention at a level of from 0.0001% to 4% active enzyme by weight of the composition.

Preferred amylases include, for example, α-amylases obtained from a special strain of B licheniformis, described in more detail in GB-1,269,839 (Novo). Preferred commercially available amylases include for example, those sold under the tradename Rapidase by Gist-Brocades, and those sold under the tradename Termamyl and BAN by Novo Industries A/S. Amylase enzyme may be incorporated into the composition in accordance with the invention at a level of from 0.0001% to 2% active enzyme by weight of the composition.

Lipolytic enzyme (lipase) may be present at levels of active lipolytic enzyme of from 0.0001% to 2% by weight, preferably 0.001% to 1% by weight, most preferably from 0.001% to 0.5% by weight of the compositions. The lipase may be fungal or bacterial in origin. Lipase from chemically or genetically modified mutants of these strains are also useful herein. A preferred lipase is described in Granted European Patent, EP-B-0218272.

An especially preferred lipase herein is obtained by cloning the gene from Humicola lanuginosa and expressing the gene in Aspergillus oryza, as host, as described in European Patent Application, EP-A-0258 068, which is commercially available from Novo Industries A/S, Bagsvaerd, Denmark, under the trade name Lipolase. This lipase is also described in U.S. Pat. No. 4,810,414, Huge-Jensen et al, issued Mar. 7, 1989.

Enzyme Stabilizing System

Preferred enzyme-containing compositions herein may comprise from about 0.001% to about 10%, preferably from about 0.005% to about 8%, most preferably from about 0.01% to about 6%, by weight of an enzyme stabilizing system. The enzyme stabilizing system can be any stabilizing system which is compatible with the detersive enzyme. Such stabilizing systems can comprise calcium ion, boric acid, propylene glycol, short chain carboxylic acid, boronic acid, chlorine bleach scavengers and mixtures thereof. Such stabilizing systems can also comprise reversible enzyme inhibitors, such as reversible protease inhibitors.

Organic polymeric compound

Organic polymeric compounds may be added as preferred components of the compositions in accord with the invention. By organic polymeric compound it is meant essentially any polymeric organic compound commonly used as dispersants, and anti-redeposition and soil suspension agents in detergent compositions. Organic polymer compounds, however, have not been previously described as soil release agents in dishwashing.

Organic polymeric compound is typically incorporated in the detergent compositions of the invention at a level of from 0.1% to 30%, preferably from 0.5% to 15%, most preferably from 1% to 10% by weight of the compositions.

Examples of organic polymeric compounds include the water soluble organic homo- or co-polymeric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxyl radicals separated from each other by not more than two carbon atoms. Polymers of the latter type are disclosed in GB-A-1,596,756. Examples of such salts are polyacrylates of molecular weight 2000-10000 and their copolymers with any suitable other monomer units including modified acrylic, fumaric, maleic, itaconic, aconitic, mesaconic, citraconic and methylenemalonic acid or their salts, maleic anhydride, acrylamide, alkylene, vinylmethyl ether, styrene and any mixtures thereof. Preferred are the copolymers of acrylic acid and maleic anhydride having a molecular weight of from 20,000 to 100,000.

Preferred commercially available acrylic acid containing polymers having a molecular weight below 15,000 include those sold under the tradename Sokalan PA30, PA20, PA15, PA10 and Sokalan CP10 by BASF GmbH, and those sold under the tradename Acusol 45N by Rohm and Haas.

Preferred acrylic acid containing copolymers include those which contain as monomer units: a) from 90% to 10%, preferably from 80% to 20% by weight acrylic acid or its salts and b) from 10% to 90%, preferably from 20% to 80% by weight of a substituted acrylic monomer or its salts having the general formula --[CR₂ --CR₁ (CO--O--R₃)]-- wherein at least one of the substituents R₁, R₂ or R₃, preferably R₁ or R₂ is a 1 to 4 carbon alkyl or hydroxyalkyl group, R₁ or R₂ can be a hydrogen and R₃ can be a hydrogen or alkali metal salt. Most preferred is a substituted acrylic monomer wherein R₁ is methyl, R₂ is hydrogen (i.e. a methacrylic acid monomer). The most preferred copolymer of this type has a molecular weight of 3500 and contains 60% to 80% by weight of acrylic acid and 40% to 20% by weight of methacrylic acid.

The polyamino compounds are useful herein including those derived from aspartic acid such as those disclosed in EP-A-305282, EP-A-305283 and EP-A-351629.

Clay softening system

The detergent compositions may contain a clay softening system comprising a clay mineral compound and optionally a clay flocculating agent.

The clay mineral compound is preferably a smectite clay compound. Smectite clays are disclosed in the U.S. Pat. Nos. 3,862,058, 3,948,790, 3,954,632 and 4,062,647. European Patents Nos. EP-A-299,575 and EP-A-313,146 in the name of the Procter and Gamble Company describe suitable organic polymeric clay flocculating agents.

Lime soap dispersant compound

The compositions of the invention may contain a lime soap dispersant compound, preferably present at a level of from 0.1% to 40% by weight, more preferably 1% to 20% by weight, most preferably from 2% to 10% by weight of the compositions.

A lime soap dispersant is a material that prevents the precipitation of alkali metal, ammonium or amine salts of fatty acids by calcium or magnesium ions. Preferred lime soap dispersant compounds are disclosed in PCT application No. WO93/08877.

Suds suppressing system

The compositions of the invention, when formulated for use in machine washing compositions, preferably comprise a suds suppressing system present at a level of from 0.01% to 15%, preferably from 0.05% to 10%, most preferably from 0.1% to 5% by weight of the composition.

Suitable suds suppressing systems for use herein may comprise essentially any known antifoam compound, including, for example silicone antifoam compounds, 2-alkyl and alcanol antifoam compounds. Preferred suds suppressing systems and antifoam compounds are disclosed in PCT application No. WO93/08876 and copending European Application No. 93870132.3.

Polymeric dye transfer inhibiting agents

The compositions herein may also comprise from 0.01% to 10%, preferably from 0.05% to 0.5% by weight of polymeric dye transfer inhibiting agents.

The polymeric dye transfer inhibiting agents are preferably selected from polyamine N-oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, polyvinylpyrrolidonepolymers or combinations thereof.

Optical brightener

The detergent compositions herein also optionally contain from about 0.005% to 5% by weight of certain types of hydrophilic optical brighteners.

Hydrophilic optical brighteners useful herein include those having the structural formula: ##STR21## wherein R₁ is selected from anilino, N-2-bis-hydroxyethyl and NH-2-hydroxyethyl; R₂ is selected from N-2-bis-hydroxyethyl, N-2-hydroxyethyl-N-methylamino, morphilino, chloro and amino; and M is a salt-forming cation such as sodium or potassium.

When in the above formula, R₁ is anilino, R₂ is N-2-bis-hydroxyethyl and M is a cation such as sodium, the brightener is 4,4',-bis[(4-anilino-6-(N-2-bis-hydroxyethyl)-s-triazine-2-yl)amino]-2,2'-stilbenedisulfonic acid and disodium salt. This particular brightener species is commercially marketed under the tradename Tinopal-UNPA-GX by Ciba-Geigy Corporation. Tinopal-UNPA-GX is the preferred hydrophilic optical brightener useful in the detergent compositions herein.

When in the above formula, R₁ is anilino, R₂ is N-2-hydroxyethyl-N-2-methylamino and M is a cation such as sodium, the brightener is 4,4'-bis[(4-anilino-6-(N-2-hydroxyethyl-N-methylamino)-s-triazine-2-yl)amino]2,2'-stilbenedisulfonic acid disodium salt. This particular brightener species is commercially marketed under the tradename Tinopal 5BM-GX by Ciba-Geigy Corporation.

When in the above formula, R₁ is anilino, R₂ is morphilino and M is a cation such as sodium, the brightener is 4,4'-bis[(4-anilino-6-morphilino-s-triazine-2-yl)amino]2,2'-stilbenedisulfonic acid, sodium salt. This particular brightener species is commercially marketed under the tradename Tinopal AMS-GX by Ciba Geigy Corporation.

Cationic fabric softening agents

Cationic fabric softening agents can also be incorporated into compositions in accordance with the present invention. Suitable cationic fabric softening agents include the water insoluble tertiary amines or dilong chain amide materials as disclosed in GB-A-1 514 276 and EP-B-0 011 340.

Cationic fabric softening agents are typically incorporated at total levels of from 0.5% to 15% by weight, normally from 1% to 5% by weight.

Other optional ingredients

Other optional ingredients suitable for inclusion in the compositions of the invention include perfumes, colours and filler salts, with sodium sulfate being a preferred filler salt.

pH of the compositions

The detergent compositions used in the present invention are preferably not formulated to have an unduly high pH, in preference having a pH measured as a 1% solution in distilled water of from 8.0 to 12.5, more preferably from 9.0 to 11.8, most preferably from 9.5 to 11.5.

Form of the compositions

The detergent compositions used in this invention can be formulated in any desirable form such as powders, granulates, pastes, liquids, gels and tablets, granular and tablet forms being preferred.

The bulk density of the granular detergent compositions in accordance with the present invention is typically of at least 650 g/liter, more usually at least 700 g/liter and more preferably from 800 g/liter to 1200 g/liter.

The particle size of the components of granular compositions in accordance with the invention should preferably be such that no more that 5% of particles are greater than 1.4 mm in diameter and not more than 5% of particles are less than 0.15 mm in diameter.

Compacted solids may be manufactured using any suitable compacting process, such as tabletting, briquetting or extrusion, preferably tabletting. Preferably tablets are manufactured using a standard rotary tabletting press using compression forces of from 5 to 13 KN/cm², more preferably from 5 to 11 KN/cm² so that the compacted solid has a minimum hardness of 176N to 275N, preferably from 195N to 245N, measured by a C100 hardness test as supplied by I. Holland instruments. This process may be used to prepare homogeneous or layered tablets of any size or shape. Preferably tablets are symmetrical to ensure the uniform dissolution of the tablet in the wash solution.

According to the present invention the compacted solid form detergent composition may find utility in all types of automatic dish- and laundry washing machines including industrial and domestic machines.

Generally, if the compositions are in liquid form the liquid should be thixotropic (ie; exhibit high viscosity when subjected to low stress and lower viscosity when subjected to high stress), or at least have very high viscosity, for example, of from 1,000 to 10,000,000 centipoise.

Machine dishwashing method

Any suitable methods for machine washing or cleaning soiled tableware, particularly soiled silverware are envisaged.

A preferred machine dishwashing method comprises treating soiled articles selected from crockery, glassware, hollowware, silverware and cutlery and mixtures thereof, with an aqueous liquid having dissolved or dispensed therein an effective amount of a machine dishwashing composition in accord with the invention. By an effective amount of the machine dishwashing composition it is meant from 8 g to 60 g of product dissolved or dispersed in a wash solution of volume from 3 to 10 liters, as are typical product dosages and wash solution volumes commonly employed in conventional machine dishwashing methods.

Laundry washing method

Machine laundry methods herein typically comprise treating soiled laundry with an aqueous wash solution in a washing machine having dissolved or dispensed therein an effective amount of a machine laundry detergent composition in accord with the invention. By an effective amount of the detergent composition it is meant from 40 g to 300 g of product dissolved or dispersed in a wash solution of volume from 5 to 65 liters, as are typical product dosages and wash solution volumes commonly employed in conventional machine laundry methods.

In a preferred use aspect a dispensing device is employed in the washing method. The dispensing device is charged with the detergent product, and is used to introduce the product directly into the drum of the washing machine before the commencement of the wash cycle. Its volume capacity should be such as to be able to contain sufficient detergent product as would normally be used in the washing method.

Once the washing machine has been loaded with laundry the dispensing device containing the detergent product is placed inside the drum. At the commencement of the wash cycle of the washing machine water is introduced into the drum and the drum periodically rotates. The design of the dispensing device should be such that it permits containment of the dry detergent product but then allows release of this product during the wash cycle in response to its agitation as the drum rotates and also as a result of its contact with the wash water.

To allow for release of the detergent product during the wash the device may possess a number of openings through which the product may pass. Alternatively, the device may be made of a material which is permeable to liquid but impermeable to the solid product, which will allow release of dissolved product. Preferably, the detergent product will be rapidly released at the start of the wash cycle thereby providing transient localised high concentrations of product in the drum of the washing machine at this stage of the wash cycle.

Preferred dispensing devices are reusable and are designed in such a way that container integrity is maintained in both the dry state and during the wash cycle. Especially preferred dispensing devices for use with the composition of the invention have been described in the following patents; GB-B-2, 157, 717, GB-B-2, 157, 718, EP-A-0201376, EP-A-0288345 and EP-A-0288346. An article by J. Bland published in Manufacturing Chemist, November 1989, pages 41-46 also describes especially preferred dispensing devices for use with granular laundry products which are of a type commonly know as the "granulette". Another preferred dispensing device for use with the compositions of this invention is disclosed in PCT patent application No. WO94/11562.

Especially preferred dispensing devices are disclosed in European Patent Application Publication Nos. 0343069 & 0343070. The latter application discloses a device comprising a flexible sheath in the form of a bag extending from a support ring defining an orifice, the orifice being adapted to admit to the bag sufficient product for one washing cycle in a washing process. A portion of the washing medium flows through the orifice into the bag, dissolves the product, and the solution then passes outwardly through the orifice into the washing medium. The support ring is provided with a masking arrangement to prevent egress of wetted, undissolved, product, this arrangement typically comprising radially extending walls extending from a central boss in a spoked wheel configuration, or a similar structure in which the walls have a helical form.

Alternatively, the dispensing device may be a flexible container, such as a bag or pouch. The bag may be of fibrous construction coated with a water impermeable protective material so as to retain the contents, such as is disclosed in European published Patent Application No. 0018678.

Alternatively it may be formed of a water-insoluble synthetic polymeric material provided with an edge seal or closure designed to rupture in aqueous media as disclosed in European published Patent Application Nos. 0011500, 0011501, 0011502, and 0011968. A convenient form of water frangible closure comprises a water soluble adhesive disposed along and sealing one edge of a pouch formed of a water impermeable polymeric film such as polyethylene or polypropylene.

EXAMPLES

The following cleaning compositions were prepared (parts by weight).

Abbreviations used in Examples

In the detergent compositions, the abbreviated component identifications have the following meanings:

    ______________________________________                                         LAS         Sodium linear C.sub.12 alkyl benzene sulfonate                     TAS         Sodium tallow alkyl sulfate                                        C45AS       Sodium C.sub.14 --C.sub.15 linear alkyl sulfate                    CxyEzS      Sodium C.sub.1x --C.sub.1y branched alkyl sulfate                              condensed with z moles of ethylene oxide                           C45E7       A C.sub.14-15 predominantly linear primary                                     alcohol condensed with an average of 7 moles                                   of ethylene oxide                                                  C25E3       A C.sub.14-15 branched primary alcohol condensed                               with an average of 3 moles of ethylene oxide                       C25E5       A C.sub.12-15 branched primary alcohol condensed                               with an average of 5 moles of ethylene oxide                       CEQ         R.sub.1 COOCH.sub.2 CH.sub.2.N .sup.+  (CH.sub.3).sub.3 with                   R.sub.1 = C.sub.11 --C13                                           QAS         R.sub.2.N .sup.+  (CH.sub.3).sub.2 (C.sub.2 H.sub.4 OH with                    R.sub.2 = C.sub.12 --C.sub.14                                      Soap        Sodium linear alkyl carboxylate derived from                                   an 80/20 mixture of tallow and coconut oils                        TFAA        C.sub.16 --C.sub.18 alkyl N-methyl glucamide                       TPKFA       C.sub.12 --C.sub.14 topped whole cut fatty acids                   Zeolite A   Hydrated Sodium Aluminosilicate of formula                                     Na.sub.12 (A10.sub.2 SiO.sub.2).sub.12.27H.sub.2 O having a                    primary                                                                        particle size in the range from 0.1 to 10                                      micrometers                                                        Zeolite MAP Hydrated sodium aluminosilicate MAP having                                     a silicon to aluminium ratio of 1.07:1.                            NaSKS-6     Crystalline layered silicate of formula                                        δ-Na.sub.2 Si.sub.2 O.sub.5                                  Citric Acid Anhydrous citric acid                                              Bicarbonate Anhydrous sodium bicarbonate with a particle                                   size distribution between 400 μm and 1200 μm                 MA/AA       Copolymer of 1:4 maleic/acrylic acid, average                                  molecular weight about 70,000                                      CMC         Sodium carboxymethyl cellulose                                     Alcalase    Proteolytic enzyme of activity 3AU/g sold by                                   NOVO Industries A/S                                                Cellulase   Cellulytic enzyme of activity 1000 CEVU/g                                      sold by NOVO Industries AIS under the                                          tradename Carezyme                                                 Lipase      Lipolytic enzyme of activity 100 kLU/g sold by                                 NOVO Industries A/S under the tradename                                        Lipolase                                                           Endolase    Endoglucase enzyme of activity 3000 CEVU/g                                     sold by NOVO Industries A/S                                        Photoactivated                                                                             Sulfonated Zinc Phythlocyanine encapsulated in                     bleach      dextrin soluble polymer                                            Brightener 1                                                                               Disodium 4,4'-bis(2-sulphostyryl)biphenyl                          Brightener 2                                                                               Disodium 4,4'-bis (4-anilino-6-morpholino-                                     1.3.5-triazin-2-yl)amino) stilbene-2:2'-                                       disulfonate                                                        PVNO        Polyvinylpyridine N-oxide                                          PVPVI       Copolymer of polyvinylpyrolidone and                                           vinylimidazole                                                     SRP 1       Sulfobenzoyl end capped esters with                                            oxyethylene oxy and terephtaloyl backbone                          SRP 2       Diethoxylated poly (1, 2 propylene terephtlate)                                short block polymer                                                Silicone    Polydimethylsiloxane foam controller with                          antifoam    siloxane-oxyalkylene copolymer as dispersing                                   agent with a ratio of said form controller to                                  said dispersing agent of 10:1 to 100:1                             NOBS        Nonanoyloxybenzene sulfonate in the form of                                    the sodium salt                                                    STPP        Sodium tripolyphosphate                                            MGDA-fast   Particle comprising methyl glycine diacetic                        release     acid and magnesium sulfate at a weight ratio of                    particle    1:3 (T50 < 100 seconds)                                            MGDA        Methyl Glycine Diacetic acid                                       Citrate     Tri-sodium citrate dihydrate                                       Carbonate   Anhydrous sodium carbonate                                         Silicate    Amorphous Sodium Silicate (SiO.sub.2 :Na.sub.2 O ratio                         = 2.0)                                                             Metasilicate                                                                               Sodium metasilicate (SiO.sub.2 :Na.sub.2 O ratio = 1.0)            PB1         Anhydrous sodium perborate monohydrate                             PB4         Sodium perborate tetrahydrate of nominal                                       formula NaBO.sub.2.3H.sub.2 O.H.sub.2 O.sub.2                      Percarbonate                                                                               Anhydrous sodium percarbonate of nominal                                       formula 2.Na.sub.2 CO.sub.3.3H.sub.2 O.sub.2                       Nonionic    C.sub.13 --C.sub.15 mixed ethoxylated/propoxylated fatty                       alcohol with an average degree of ethoxylation                                 of 3.8 and an average degree of propoxylation                                  of 4.5 sold under the tradename Plurafac                                       LF404 by BASF GmbH (low foaming)                                   TAED        Tetraacetyl ethylene diamine                                       HEDP        Ethane 1-hydroxy-1,1-diphosphoric acid                             DETPMP      Diethyltriamine penta (methylene)                                              phosphonate, marketed by monsanto under the                                    tradename Dequest 2060                                             PAAC.sub.   Pentaamine acetate cobalt (III) salt                               BzP         Benzoyl Peroxide                                                   Paraffin    Paraffin oil sold under the tradename Winog 70                                 by Wintershall.                                                    Protease    Proteolytic enzyme of activity 4 KNPU/g sold                                   under the tradename Savinase by Novo                                           Industries A/S                                                     Amylase     Amylolytic enzyme of activity 60 KNU/g sold                                    under tradename Termamyl 60T by Novo                                           Industries A/S                                                     BTA         Benzotriazole                                                      Bismuth nitrate                                                                            Bismuth nitrate salt                                               PA30        Polyacrylic acid of average molecular weight                                   approximately 8,000                                                Terpolymer  Terpolymer of average molecular weight                                         approx. 7,000, comprising                                                      acrylic:maleic:ethylacrylic acid monomer units                                 at a weight ratio of 60:20:20                                      480N        Random copolymer of 3:7 acrylic/methacrylic                                    acid, average molecular weight about 3,500                         Sulphate    Anhydrous sodium sulphate.                                         NaDCC       Sodium dichloroisocyanurate                                        KOH         100% active solution of Potassium Hydroxide                        BSA         Amylotic enzyme sold under the tradename                                       LE17 by Novo Industries A/S (approx 1%                                         enzyme activity)                                                   pH          Measured as a 1% solution in distilled water at                                20° C.                                                      ______________________________________                                    

In the following examples all levels are quoted as % by weight of the composition:

Example 1

The following compact high density (0.96 Kg/l) dishwashing detergent compositions A to F were prepared in accord with the invention:

    ______________________________________                                                   A    B       C      D     E    F                                     ______________________________________                                         STPP        24.80  24.80   25.00                                                                               28.39 28.50                                                                               20.00                               Citrate     --      --     --   --    10.00                                                                               10.00                               Carbonate   --     --      17.50                                                                               17.50 --   --                                  MGDA fast release                                                                          1.00   2.50    2.00 2.00  3.00 2.00                                particle                                                                       Silicate    20.36  20.36   14.81                                                                               14.81 14.81                                                                               --                                  Metasilicate                                                                               2.50   2.50    2.50 --    --   --                                  PB1         7.79   7.79    9.74 14.28 9.74 --                                  PB4         --     --      --   --    --   --                                  Percarbonate                                                                               --     --      --   --    --   6.70                                Non-ionic   1.50   1.50    2.00 1.50  2.00 2.60                                TAED        2.39   2.39    2.39 --    --   4.00                                HEDP        0.46   0.46    1.00 --    0.83 --                                  DETPMP      --     --      0.65 --    --   --                                  PAAC        --     --      --   0.20  --   --                                  BzP         --     --      --   4.44  --   --                                  Paraffin    0.50   0.50    0.50 0.50  --   0.20                                Protease    2.20   2.20    2.20 2.20  2.00 0.50                                Amylase     1.50   1.50    1.20 1.50  1.00 1.10                                BTA         0.30   0.30    0.30 0.30  --   --                                  Bismuth Nitrate                                                                            --     --      0.30 --    --   --                                  PA30        --     --      --   --    --   --                                  Terpolymer  --     --      --   4.00  --   --                                  480N        2.77   2.77    6.00 --    6.67 --                                  Sulphate    8.44   8.44    20.77                                                                               --    23.24                                                                               1.00                                Misc inc moisture                                                              to balance                                                                     pH (1% solution)                                                                           10.90  10.90   11.00                                                                               10.80 10.90                                                                               9.60                                ______________________________________                                    

Example 2

The following granular dishwashing detergent compositions examples G to L of bulk density 1.02 Kg/L were prepared in accord with the invention:

    ______________________________________                                                  G     H      I        J    K     L                                    ______________________________________                                         STPP       30.00   30.00  30.00  27.90                                                                               34.50 26.70                              Carbonate  30.50   23.50  30.50  23.00                                                                               30.50 2.80                               MGDA fast release                                                                         1.00    2.00   2.00   5.00 5.00  2.00                               particle                                                                       Silicate   7.40    7.40   7.40   12.00                                                                               8.00  18.34                              PB1        4.40    4.40   4.40   --    4.40 --                                 NaDCC      --      --     --     2.00 --    1.50                               Nonionic   0.75    0.75   0.75   1.90 1.20  0.50                               TAED       1.00    1.00   --     --   1.00  --                                 PAAC       --      --     0.004  --   --    --                                 BzP        --      1.40   --     --   --    --                                 Paraffin   0.25    0.25   0.25   --   --    --                                 Protease   1.10    1.10   1.10   --   2.20  --                                 Amylase    0.38    0.38   0.38   --   0.80  --                                 BTA        0.15    --     0.15   --   --    --                                 Sulphate   23.90   21.90  21.90  26.40                                                                               12.40 --                                 Misc inc moisture                                                              to balance                                                                     pH (1% solution)                                                                          10.80   10.80  10.80  10.70                                                                               10.70 12.30                              ______________________________________                                    

Example 3

The following detergent composition tablets in accord with the present invention of 25 g weight were prepared by compression of a granular dishwashing detergent composition comprising all of the components except MGDA at a pressure of 13 KN/cm² using a standard 12 head rotary press. The MGDA was then sprayed onto the outermost surface of the tablet.

    ______________________________________                                                     M        N       O                                                 ______________________________________                                         STPP          45.00      38.80   32.50                                         Citrate       --         --      15.00                                         Carbonate     --         5.00    --                                            MGDA          4.00       4.00    2.00                                          Silicate      26.40      14.80   25.00                                         Protease      1.76       2.20    0.60                                          Amylase       1.20       --      0.60                                          PB1           1.56       7.79    --                                                          6.92       --      11.40                                         Nonionic      1.20       2.00    1.10                                          TAED          4.33       2.39    0.80                                          HEDP          0.67       0.67    --                                            DETPMP        0.65       --      --                                            Paraffin      0.42       0.50    --                                            BTA           0.24       0.30    --                                            PA30          3.2        --      --                                            Sulphate      25.05      12.70   1.20                                          Misc inc moisture to                                                           balance                                                                        pH (1% solution)                                                                             10.60      10.60   11.00                                         ______________________________________                                    

Example 4

The following liquid detergent compositions in accord with the present invention P to Q, of density 1.40 Kg/L were prepared:

    ______________________________________                                                           P     Q                                                      ______________________________________                                         STPP                31.30   18.00                                              Carbonate           2.70    2.00                                               MGDA                2.00    2.00                                               Silicate            --      4.40                                               NaDCC               1.10    1.15                                               Nonionic            2.50    1.00                                               Paraffin            2.20    --                                                 Protease            0.60    0.50                                               Amylase             0.80    0.40                                               480N                0.50    4.00                                               KOH                 --      6.00                                               Sulphate            1.60    --                                                 Misc inc moisture to balance                                                   pH (1 % solution)   9.10    10.00                                              ______________________________________                                    

Example 5

The following granular laundry detergent compositions A' to C' of bulk density 750 g/liter were prepared in accord with the invention:

    ______________________________________                                                     A'        B'      C'                                               ______________________________________                                         LAS           5.25        5.61    4.76                                         TAS           1.25        1.86    1.57                                         C45AS         --          2.24    3.89                                         C25AE3S       --          0.76    1.18                                         C45E7         3.25        --      5.0                                          C25E3         --          5.5     --                                           CEQ           0.8         2.0     2.0                                          STPP          19.7        19.5    19.5                                         MGDA fast release                                                                            2.0         2.0     2.0                                          particle                                                                       Zeolite A     --          19.5    19.5                                         NaSKS-6/citric acid                                                                          --          10.6    10.6                                         (79:21)                                                                        Carbonate     6.1         21.4    21.4                                         Bicarbonate   --          2.0     2.0                                          Silicate      6.8         --      --                                           Sodium sulfate                                                                               39.8        --      14.3                                         PB4           5.0         12.7    --                                           TAED          0.5         3.1     --                                           DETPMP        0.25        0.2     0.2                                          HEDP          --          0.3     0.3                                          Protease      0.26        0.85    0.85                                         Lipase        0.15        0.15    0.15                                         Cellulase     0.28        0.28    0.28                                         Amylase       0.1         0.1     0.1                                          MA/AA         0.8         1.6     1.6                                          CMC.sub.      0.2         0.4     0.4                                          Photoactivated bleach                                                                        15 ppm      27 ppm  27 ppm                                       (ppm)                                                                          Brightener 1  0.08        0.19    0.19                                         Brightener 2  --          0.04    0.04                                         Perfume       0.3         0.3     0.3                                          Silicone antifoam                                                                            0.5         2.4     2.4                                          Minors/misc to 100%                                                            ______________________________________                                    

Example 6

The following detergent compositions, according to the present invention were prepared:

    ______________________________________                                                       D'      E'      F'                                               ______________________________________                                         Blown Powder                                                                   STPP            24.0      --       24.0                                        Zeolite A       --        24.0    --                                           C4SAS           9.0       6.0     13.0                                         MA/AA           2.0       4.0     2.0                                          LAS             6.0       8.0     11.0                                         TAS             2.0       --      --                                           Silicate        7.0       3.0     3.0                                          CMC             1.0       1.0     0.5                                          Brightener 2    0.2       0.2     0.2                                          Soap            1.0       1.0     1.0                                          DTPMP           0.4       0.4     0.2                                          Spray On                                                                       C45E7           2.5       2.5     2.0                                          C25E3           2.5       2.5     2.0                                          Silicone antifoam                                                                              0.3       0.3     0.3                                          Perfume         0.3       0.3     0.3                                          Dry additives                                                                  Carbonate       6.0       13.0    15.0                                         MGDA fast release particle                                                                     2.0       2.0     2.0                                          PB4             18.0      18.0    10.0                                         PB1             4.0       4.0     0                                            TAED            3.0       3.0     1.0                                          Photoactivated bleach                                                                          0.02      0.02    0.02                                         Protease        1.0       1.0     1.0                                          Lipase          0.4       0.4     0.4                                          Amylase         0.25      0.30    0.15                                         Dry mixed sodium sulfate                                                                       3.0       3.0     5.0                                          Balance (Moisture &                                                                            100.0     100.0   100.0                                        Miscellaneous)                                                                 Density (g/litre)                                                                              630       670     670                                          ______________________________________                                    

Example 7

The following nil bleach-containing detergent formulations of particular use in the washing of colored clothing, according to the present invention were prepared:

    ______________________________________                                                          G'    H'                                                      ______________________________________                                         Blown Powder                                                                   STPP               15.0    15.0                                                Sodium sulfate     0.0     5.0                                                 LAS                3.0     3.0                                                 DTPMP              0.4     0.5                                                 CMC                0.4     0.4                                                 MA/AA              4.0     4.0                                                 Agglomerates                                                                   C45AS              --      --                                                  LAS                6.0     5.0                                                 TAS                3.0     2.0                                                 Silicate           4.0     4.0                                                 Zeolite A          10.0    15.0                                                CMC                --      --                                                  MA/AA              --      --                                                  Carbonate          9.0     7.0                                                 Spray On                                                                       Perfume            0.3     0.3                                                 C45E7              4.0     4.0                                                 C25E3              2.0     2.0                                                 Dry additives                                                                  MA/AA              --      --                                                  MGDA fast release particle                                                                        2.0     2.0                                                 NaSKS-6            --      --                                                  Citrate            10.0    --                                                  Bicarbonate        7.0     3.0                                                 Carbonate          8.0     5.0                                                 PVPVI/PVNO         0.5     0.5                                                 Alcalase           0.5     0.3                                                 Lipase             0.4     0.4                                                 Amylase            0.6     0.6                                                 Cellulase          0.6     0.6                                                 Silicone antifoam  5.0     5.0                                                 Dry additives                                                                  Sodium sulfate     0.0     9.0                                                 Balance (Moisture and                                                                             100.0   100.0                                               Miscellaneous)                                                                 Density (g/litre)  700     700                                                 ______________________________________                                    

Example 8

The following detergent formulations, according to the present invention were prepared:

    ______________________________________                                                   I'    J'        K'     L'                                            ______________________________________                                         LAS         20.0    14.0      24.0 22.0                                        QAS         0.7     1.0       --   0.7                                         TFAA        --      1.0       --   --                                          C25E5/C45E7 --      2.0       --   0.5                                         C45E3S      --      2.5       --   --                                          STPP        30.0    18.0      30.0 22.0                                        Silicate    9.0     5.0       10.0 8.0                                         Carbonate   13.0    7.5       --   5.0                                         MGDA fast   2.0     2.0       2.0  2.0                                         release particle                                                               Bicarbonate --      7.5       --   --                                          DTPMP       0.7     1.0       --   --                                          SRP1        0.3     0.2       --   0.1                                         MA/AA       2.0     1.5       2.0  1.0                                         CMC         0.8     0.4       0.4  0.2                                         Protease    0.8     1.0       0.5  0.5                                         Amylase     0.8     0.4       --   0.25                                        Lipase      0.2     0.1       0.2  0.1                                         Cellulase    0.15    0.05     --   --                                          Photoactivated                                                                             70 ppm  45 ppm    --   10 ppm                                      bleach (ppm)                                                                   Brightener 1                                                                               0.2     0.2       0.08 0.2                                         PB1         6.0     2.0       --   --                                          NOBS        2.0     1.0       --   --                                          Balance     100     100       100  100                                         (Moisture and                                                                  Miscellaneous)                                                                 ______________________________________                                    

Example 9

The following detergent formulations, according to the present invention were prepared:

    ______________________________________                                                       M'       N'     O'                                               ______________________________________                                         Blown Powder                                                                   STPP            30.0       22.0   6.0                                          Sodium sulfate  19.0       5.0    7.0                                          MA/AA           3.0        3.0    6.0                                          LAS             14.0       12.0   22.0                                         C45A5           8.0        7.0    7.0                                          Silicate        --         1.0    5.0                                          Soap            --         --     2.0                                          Brightener 1    0.2        0.2    0.2                                          Carbonate       8.0        16.0   20.0                                         DTPMP           --         0.4    0.4                                          Spray On                                                                       C45E7           1.0        1.0    1.0                                          Dry additives                                                                  PVPVI/PVNO      0.5        0.5    0.5                                          Protease        1.0        1.0    1.0                                          Lipase          0.4        0.4    0.4                                          MGDA fast release particle                                                                     2.0        2.0    2.0                                          Amylase         0.1        0.1    0.1                                          Cellulase       0.1        0.1    0.1                                          NOBS            --         6.1    4.5                                          PB1             1.0        5.0    6.0                                          Sodium sulfate  --         6.0    --                                           Balance (Moisture and                                                                          100        100    100                                          Miscellaneous)                                                                 ______________________________________                                    

Example 10

The following high density and bleach-containing detergent formulations, according to the present invention were prepared:

    ______________________________________                                                       P'       Q'     R'                                               ______________________________________                                         Blown Powder                                                                   STPP            15.0       15.0   15.0                                         Sodium sulfate  0.0        5.0    0.0                                          LAS             3.0        3.0    3.0                                          QAS             --         1.5    1.5                                          DTPMP           0.4        0.4    0.4                                          CMC             0.4        0.4    0.4                                          MA/AA           4.0        2.0    2.0                                          Agglomerates                                                                   LAS             5.0        5.0    5.0                                          TAS             2.0        2.0    1.0                                          Silicate        3.0        3.0    4.0                                          Zeolite A       8.0        8.0    8.0                                          Carbonate       8.0        8.0    4.0                                          Spray On                                                                       Perfume         0.3        0.3    0.3                                          C45E7           2.0        2.0    2.0                                          C25E3           2.0        --     --                                           Dry additives                                                                  Citrate         5.0        --     2.0                                          MGDA fast release particle                                                                     2.0        2.0    2.0                                          Bicarbonate     --         3.0    --                                           Carbonate       8.0        15.0   10.0                                         TAED            6.0        2.0    5.0                                          PB1             14.0       7.0    10.0                                         Polyethylene oxide of MW                                                                       --         --     0.2                                          5,000,000                                                                      Bentonite clay  --         --     10.0                                         Protease        1.0        1.0    1.0                                          Lipase          0.4        0.4    0.4                                          Amylase         0.6        0.6    0.6                                          Cellulase       0.6        0.6    0.6                                          Silicone antifoam                                                                              5.0        5.0    5.0                                          Dry additives                                                                  Sodium sulfate  0.0        3.0    0.0                                          Balance (Moisture and                                                                          100.0      100.0  100.0                                        Miscellaneous)                                                                 Density (g/litre)                                                                              850        850    850                                          ______________________________________                                     

What is claimed is:
 1. A granular or tablet detergent composition comprisinga) from 0.2% to 30% by weight of the composition of a surfactant system; b) from 1% to 80% by weight of the composition of a builder; and c) from 0.001% to 40% by weight of the composition of an amino tricarboxylic acid or salt thereof wherein said amino tricarboxylic acid has the general formula: ##STR22## where R₁, R₂ and R₃ are alkyl groups or substituted alkyl groups of chain length C1 to C4; n is 0 or 1; and X is an organic substituent group; wherein said amino tricarboxylic acid has a rate of dissolution such that in the T50 test method, the time taken to achieve 50% dissolution of amino tricarboxylic acid is less than 100 seconds; and wherein said amino tricarboxylic acid or salt thereof has an average particle diameter of from 1100 to 200 micrometers and is present as a layer on the outermost surface of the composition.
 2. A detergent composition according to claim 1 wherein said amino tricarboxylic acid is methyl glycine diacetic acid.
 3. A detergent composition according to claim 1 in the form of a tablet.
 4. A detergent composition according to claim 1 the weight ratio of the surfactant system to the amino tricarboxylic acid is from 10:1 to 1:1.
 5. A detergent composition according to claim 1 wherein the weight ratio of the builder to the amino tricarboxylic acid is from 5:1 to 25:1.
 6. A detergent composition according to claim 1 wherein the detergent composition additionally comprises an oxygen-releasing bleaching system.
 7. A method for cleaning soiled articles in a machine dishwasher comprising treating soiled articles selected from the group consisting of crockery, glassware, silverware, cutlery and mixtures thereof with an aqueous liquid having the composition of claim 1 dissolved or dispensed therein.
 8. A method for cleaning soiled laundry in a washing machine comprising treating soiled laundry with an aqueous wash solution having the composition of claim 1 dissolved or dispensed therein. 